Add search and links to plugin settings (#4854)

* Show links to plugin views and settings in plugin list and in success message after activating a plugin
* Fix menu highlighting in payment provider settings
* Specify settings_links and navigation_links for built-in plugins
* Add link to payment plugins from payment settings
* Add client-side search and "View only active plugins" for plugins page

src/pretix/plugins/webcheckin/apps.py

@@ -36,6 +36,9 @@ class WebCheckinApp(AppConfig):
         experimental = True
         category = "FEATURE"
         description = _("Turn your browser into a check-in device to perform access control.")
+        navigation_links = [
+            ((_("Check-in"), _("Web Check-in")), "plugins:webcheckin:index", {}),
+        ]
 
     def ready(self):
         from . import signals  # NOQA